Thutrang T. Tran

Learn More
When laboratory populations of the RNA bacteriophage phi6 are subjected to intensified genetic drift, they experience a decline in fitness. These experiments demonstrate that the average effect of mutations is deleterious, and they are used to suggest that Muller's ratchet can operate in these viruses. However, the operation of Muller's ratchet does not(More)
RATIONALE To investigate the fragmentations in the negative-ion electrospray mass spectra of peptides containing tyrosine sulfate. METHODS Possible fragmentation mechanisms were explored using a Waters QTOF2 tandem mass spectrometer in concert with calculations at the CAM-B3LYP/6-311++g(d,p) level of theory. RESULTS The major negative ion formed in the(More)
The low-energy negative ion phosphoTyr to C-terminal -CO(2)PO(3)H(2) rearrangement occurs for energised peptide [M-H](-) anions even when there are seven amino acid residues between the pTyr and C-terminal amino acid residues. The rearranged C-terminal -CO(2)PO(2)H(O(-)) group effects characteristic S(N)i cyclisation/cleavage reactions. The most pronounced(More)
RATIONALE To use negative-ion nano-electrospray ionization mass spectrometry of peptides from the tryptic digest of ricin D, to provide sequence information; in particular, to identify disulfide position and connectivity. METHODS Negative-ion fragmentations of peptides from the tryptic digest of ricin D was studied using a Waters QTOF2 mass spectrometer(More)
An analytical procedure has been developed for the analysis of intracellular didanosine triphosphate (ddATP). An electrospray ionization tandem mass spectrometer (ESI-MS) was interfaced to liquid chromatography (LC) using a mobile phase CH3OH/H2O (25/75) containing 1% formic acid for the analysis of the 5'-triphosphate metabolite of the antiviral(More)
RATIONALE To determine the negative-ion cleavages from [M-H](-) ions of Ser sulfate-containing peptides using experiment and theory in concert. METHODS Fragmentations were explored using a Waters QTOF2 mass spectrometer in negative-ion electrospray mode, together with calculations at the CAM-B3LYP/6-311++g(d,p) level of theory. Peptides used in this study(More)
The Kyn-containing peptide FP-Kyn-L(NH(2)) is an unusual minor component of the skin peptide profile of the Australian red tree frog Litoria rubella collected from an area within a 20 kilometre radius of Alice Springs in central Australia. The structure was determined by electrospray mass spectrometry and synthesis. The major component of the skin secretion(More)
It has been shown previously that [M-H](-) anions of small peptides containing two phosphate residues undergo cyclisation of the phosphate groups, following collision-induced dissociation (CID), to form a characteristic singly charged anion A (H3P2O7(-), m/z 177). In the present study it is shown that the precursor anions derived from the diphosphopeptides(More)
When laboratory populations of the RNA bacteriophage 46 are subjected to intensified genetic drift, they experience a decline in fitness. These experiments demonstrate that the average effect of mutations is deleterious, and they are used to suggest that Muller’s ratchet can operate in these viruses. However, the operation of Muller’s ratchet does not alone(More)
RATIONALE An experimental study has shown that the structure of a β' ion proposed earlier is incorrect. Backbone cleavage β' anions have structures R(NH(-)) from systems [[RNHCH(X)CONHCH(Y)CO(2)H (or C-terminal CONH(2))-H](-) (where R is the rest of the peptide molecule and X and Y represent the α side chains of the individual amino acid residues). (More)